#include <bits/stdc++.h>

using namespace std;
#define int long long
const int inf = 0x3f3f3f3f;

void solve()
{
	int n;
	cin >> n;
	int mi = INT_MAX, ma = INT_MIN;
	for (int i = 0; i < n; i++)
	{
		int x;
		cin >> x;
		mi = min(mi, x);
		ma = max(ma, x);
	}
	cout << ma - mi << '\n';
}

signed main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int _ = 1;
	cin >> _;
	while (_--)
	{
		solve();
	}
	return 0;
}